This invention pertains to a fuel filter for a fuel dispensing pump used, for example, in gas stations, and more particularly, to a fuel filter having a water absorbing media therein and a positive shut off valve for totally shutting down the delivery of fuel when water is present, thus preventing the delivery of contaminated fuel to the tank of a vehicle.
Should fuel, such as gasoline, be contaminated with water, it would impair the operation of an internal combustion engine used in a vehicle. Thus it is desired to provide means for preventing water from entering a vehicle gas tank during a fueling operation.
The use of a water absorbing filter in a fuel system is known to prevent the passage of water in a fuel system is known, as is the use of a ball to provide a positive water shut off. See for example, Anderson U.S. Pat. No. 4,959,141, which discloses a canister having a water absorbing media therein. The open end of the canister is closed by a plate which has inlet openings therein and a central outlet opening. The passage of fuel through the canister may be blocked by a ball valve that is retained by a first deformable washer and is releasable from the first deformable washer upon attainment of a predetermined pressure differential. The ball is movable from the first deformable washer to a position to engage a valve seat formed on a second deformable washer. The use of the ball and the washers provides an arrangement that would not function smoothly over time and would not tend to seat firmly in the event contaminants were between the ball and its seat.
Several oil filter patents are known which incorporate bypass valves, see, for example, Boewe et al. U.S. Pat. No. 2,995,249 and Humbert U.S. Pat. No. 3,184,062. However, neither of these patents suggest the fuel filter with positive shut off valve of the present invention.
An object of the present invention is to provide a fuel filter which operates smoothly and efficiently over a period of time to prevent water from entering a vehicle gas tank during a fueling operation.
Another object of the present invention is to provide a fuel filter with a positive shutoff valve comprising a valve cylinder cup and a valve piston positioned within the fuel filter shell so as to retain the compactness desired for the shell and to operate smoothly and positively over the life of the fuel filter.
Other objects and advantages of the present invention will be made more apparent hereinafter.